Add link to sys.exit function documentation (#102805)

* Add link to `sys.exit` function documentation

* Update Doc/library/os.rst

Co-authored-by: Ezio Melotti <[email protected]>

* Update Doc/library/os.rst

Co-authored-by: C.A.M. Gerlach <[email protected]>

---------

Co-authored-by: Ezio Melotti <[email protected]>
Co-authored-by: C.A.M. Gerlach <[email protected]>

Author: 3 people

Doc/library/os.rst

@@ -3951,7 +3951,7 @@ to be ignored.
 
    .. note::
 
-      The standard way to exit is ``sys.exit(n)``.  :func:`_exit` should
+      The standard way to exit is :func:`sys.exit(n) <sys.exit>`.  :func:`!_exit` should
       normally only be used in the child process after a :func:`fork`.
 
 The following exit codes are defined and can be used with :func:`_exit`,